mojoPortal is an accessible, compliant, extensible, cross platform, cross database, content management system CMS written in C# ASP.NET. If you know how to make an ASP.NET UserControl then you already know how to make a feature that plugs into mojoPortal

Hathi, P2P client. Rewritten in C#, using mono and .net, for linux and windows platforms. Initial networking support for edonkey, with bittorrent in planning. We are looking for contributors!! Back in action after some busy days :)

ePresence was an open source project maintained by the University of Toronto from 2001 to 2008. It has been forked and commercialized in 2008 by the lab ex-employees as a private enterprise. Please visit http://epresence.tv for further details.